Method of forming abrasive articles



Oct. 1, '19 35. F. K. BEZZENBERGER METHOD OF FORMING ABRASIVE ARTICLES Filed Jan. 4, 1953 -2 Sheets-Sheet 1 I II/I IIII IUUUUUUEILIUUHUU Oct. 1, 1935. F. K. BEZZENBERGER METHOD OF FORMING ABRASIVE ARTICLES Filed Jan. 4, 1955 Z Sheets-Sheet 2 v IN VEN TOR. ze'aewzi lfie ezriezjrf ATTORNEYJ) Patented Oct. 1, 19351 UNITED STATES PATENT OFFICE METHOD OF FORMING ABRAsrvE narrows Application January 4, 1933, Serial No. 650,096

18 Claims.

The present invention relates to a method of forming abrasive articles and, more particularly, to an improved method of making sandpaper, and the like.

Ordinary sandpaper has heretofore been made by coating a sheet of paper with glue, sprinkling particles of abrasive such as garnet, silicon carbide, and the like thereon, and then rolling the abrasive particles into the glue in order to secure a sufficient bond between the particles and the glue to retain the former on the paper in use. Sometimes a sizing layer-of thin glue is applied after the rolling operation, covering exposed surfaces-of the particles in order further to insure that the particles will remain in place. Sandpaper as so made is not uniform since the abrasive particles cannot be sprinkled evenly over the surface of the paper and are found to bemore concentrated in some spots than in others, with the result that some of the particles are not securely glued to the paper and may be readily brushed off before or during use. Another objection to such paper is that the particles are pressed so far intothe glue by the subsequent rolling that a large portion of the particle is submerged in the glue and not available for abraiding purposes with the result that the sandpaper is used up and must be discarded long before any considerable proportion of the particle body is consumed. The sizing glue placed over the particles also accelerates the consumption of the sandpaper since this glue becomes hot, due to friction between the sheet and the work, and flows down between the particles, where it retains ground-off material and builds up to load and mask the abrasive particles.

It has also been the practice to prepare sandpaper and the like with the abrasive particles distributed over the entire surface of the sheet, no

special provision being made to prevent loading, the paper then being used until the particles wear down and the paper loads up with ground-oil? material to prevent further abrasive action. The paper must then be discarded even though the abrasive particles themselves are still largely unworn.

By the method herein to be described, the foregoing objections are largely overcome by distributing the abrasive particles more nearly uniformly over the glued surface of a sheet and by applying the particles to the glue with just the right amount of pressure to insure a firm bond between the paper and the abrasive particles, but without embedding the particles in the glue to an excessive degree such as would shorten the life of the paper and without the need of applying a sizing coat of glue which would accelerate the loading of the paper with the same effect.

It is, accordingly, an object of the present invention to provide a method of making an abrasive article which results in a sandpaper having 5 surfaces and of their volume exposed above the glue line. Still another object of the invention isto provide' a method of making abrasive elements which is more convenient and quicker than those now in use. A still further object is to pro- 20 vide a method of making abrasive elements in which a rolling operation rolling the abrasive particles down into the glue is avoided and in which the application, of a sizing coat over the rolled-in particles is not necessary. And still an- 5 other object of the invention is to provide a method of making abrasive, articles whereby the abrasive may be applied to its base in discontinu-- ous areas separated by areas free of abrasive. To the accomplishment of the foregoing and related 30 ends, said invention, then, consists of the steps hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail one approved method 35 of carrying out the invention, such disclosed method however, constitutingbut one of the varin Figs. 2 and 3 respectively; Fig. '7 is a fragmentary view of an abrasive article prepared by the 50 use of the apparatusshown in Fig. 1; and Fig. 8 is a sectional elevation of a type of abrasive article as shown in Fig. 5.

In the drawings, a quantity of abrasive particles I such as garnet or silcon carbide, is placed in a 55 sive power is less than that of warm or soft glue,

as will appear hereinafter.

The roller 3 is caused to revolve in the trough 2 and picks up on the surface 6 a layer 1 of abrasive particles which are brought up into contact with a sheet 8 of paper or other material which is to be coated with abrasive. This sheet travels from a supply roll past glue-coating means over a. heated roller 9 which is revolved adjacent the glued surface .1 I of the sheet in order to bring this glue to such a temperature that it will readily retain abrasive particles brought in contact therewith. The sheet then passes between the rolls 3 and 4 which are so adjusted by means of the turnbuckle 5 thatthe abrasive particles tare pressed into the glue surface ll asthe sheet 8 passes therebetween. The sheet then continues its travel with a layer of abrasive I2 thereon and the glue'inay then be quickly set by passing the sheet'under a heated roller l3 which contacts the back of the sheet.

As will be apparent, any desired adjustment of I the space between the rollers 3 and 4 may be secured bymeans of the turnbuckle 5 so that the abrasive particles 1 which are brought upwardly into contact with .the glued sheet 8 can be pressed into the glue a greater or less distance as desired. A few .tests will quickly determine how farthe abrasive particles must be pressed into the glue in'order that they will be retained firmly when the finished sheet is used for abrasive purposes and this amount will then not be exceeded so that a maximum proportion of each abrasive particle is left above the glue surface to do its work as a cutting agent in an abrasive operation. The abrasive particles will be readily transferred from the surface of the roller 3 to the surface of the glued sheet because the surface of this roller is purposely prepared with a degree of adhesiveness less than that of the glued sheet. Adjustments between the two surfaces may be made by altering the composition and the. temperature of the surface of the roller 3 and also by heating the glued surface II by means of the roller! to the exact degree of softness desired. Thus the abrasive particles on theroller 3 are immediately removed by the glued sheet upon contact, the glued sheet passing onward with its coating of abrasive and the roller picking up a new layer of abrasive from the trough 2. I

Due to the limitedadhesive power of the surface of the roller 3, this surface will pick up abrasive particles uniformly over its entire area and, since it has a relatively smooth even surface, it

will pick up but one layer of particles with little or no tendency to pile one particle on top of an-' other. When this uniform layer of particles is, in turn, transferred to the glued sheet 8, the particles are transferred in a uniform relation and an abrasive article having its abrasive particles 'uniformly distributed results. This is an effect not heretofore obtainable due to the fact that the abrasive particles have been directly sprinkled upon the glued-sheet with the result that the distribution was not uniform and there was a considerable tendency for particles to rest on top of others.

The above described method results in an improved abrasive article in which the abrasive is uniformly distributed over the entire surface of a sheet, but the present invention also contemplates a method of preparing sandpaper and the like in which the abrasive is distributed according to a determined pattern, some areas of the 1 sheet being covered .with abrasive and other areas being left free of abrasive. Where it is desired toprepare a sheet suchas that shown in Fig. 5 having diagonally disposed strips l4 covered with abrasive and alternating with strips l5 left free of l abrasive, the roller I6 shown in Fig.2 may be used. This roller has lands I'I alternating with grooves iii in which a glue and glycerine compositon l 9 of limited adhesive power may be disposed. When this roller is brought in contact with a supply of 2 abrasive particles, only the adhesive surfaces will pick up abrasive, and this will, in turn, be transferred in a definite pattern to the paper or other 'in an abrasive article having the pattern shown in Fig. 6 in which the paper 23 carries circular areas 24 covered with abrasive and separated by intervening areas 25 not so covered.

' The abrasive distributed in the above described 3 patterns is deposited in accordance with the -method herein set forth, the abrasive particles being uniformly distributed within the covered areas'and each of the particles projecting above the glue line approximately one-half or more. 4

Where the abrasive is not distributed according to a pattern, it will be uniformly disposed over the entire surface of the base as on the sheet 26 shown in Fig.- '7. Theinvention contemplates the use of the improved method to prepare abrasive articles 4 according to any of the patterns described or actachment to the backing, a greater sharpness and "6 hence a greater cutting effect of the grains due to their greater exposure, and due also to the absence of any film of adhesive over the exposed surfaces of the grains.

My improved, method presents various imporc tant advantages including the firm and rapid selective setting of the abrasive grains in the coating of adhesive on the back, and by the method described it is possible to secure a much more even and uniform mounting of the individual more or. 7 less irregular particles in the adhesive than by former methods. Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the meth- 7 particles over asurface having limited adhesive 0d herein disclosed, provided the step or steps stated by any of the following claims or the equivalent of such stated step or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. -A method of manufacturing an abrasive article which comprises depositing abrasive particles on a surface and bringing said particles in contact with another surface having a greater adhesive power than said first-named surface.

2. A method of making an abrasive article which comprises distributing individual abrasive ticle which comprises depositing abrasive particles onto a surface and. bringing said particles while so deposited in contact with another surface having a greater adhesive power than said first-named surface to transfer said abrasive particles to said other surface.

4. A method of making an abrasive article which comprises applying a surface having limited adhesive power to a mass of loose abrasive particles, picking up a uniform layer of said particles on said surface, and then bringing said surface with its coating of abrasive particles into contact with another surface having greater adhesive power than said first-named surface to transfer said particles permanently to said other surface.

- 5. A method of making an abrasive article which comprises applying a surface having approximately the adhesive power of a printer's platen roll to a mass of loose abrasive particles, picking up a layer of said particles on said surface and removing said particles from said surface by means of a surface having greater adhesive power than said first-namedsurface.

6. A method of making an abrasive article which comprises revolving a roll having a surface of limited adhesive power in contact with loose abrasive. particles, picking up said abrasive particles on said roll, passing a surface having greater adhesive power than said roll in contact with the abrasive particles on said roll, removing said particles from said roll and retaining the same on said surface of greater adhesive power.

7. A method of making an abrasive article which comprises revolving a roller having approximately the adhesive power of a printers platen roll in contact with loose abrasiveparticles picking up a layer of abrasive particles on said roller, passing the coated roller in contact with a glued sheet and transferring the abrasive particles to said sheet. r

8. A method of making an abrasive article which comprises revolving a roller having a glue and glycerine surface in contact with loose abrasive particles, picking up a layer of abrasive particles on the surface of said roller, passing the coated roll in contact with a travelling sheet covered with soft glue, and printing said abrasive particles on said sheet.

9. A method of making an abrasive article which comprises passing a sheet coated with softened glue over a roller carrying abrasive particles in a medium having less adhesion for said particles than said softened glue.

10. A method of making an abrasive article which comprises transferring abrasive particles from a pile of the loose particles to a surface coated with warm glue by means of an. intermediate surface having sumcient adhesive power to pick up the particles but less adhesive power than said warm glue.

11. A method of making an abrasive article which comprises collecting abrasive on a surface having limited adhesive power and transferring said particles in a prearranged pat-- tern to a base having greater adhesive power said first named surface.

12. A method of making an: abrasive article which comprises collecting abrasive particles: on.

- a surface having discontinuous areas limited power than the. material on said. roller, and transferring said. abrasive to said sheet in a pattern. determined by the adhesive portions of. the sur-- face of said roller.

14. A method of" making an abrasive article which comp-rises picking up abrasive particles on I the surface of a roller having portions of; its surface provided with a glue and glycerinecomposition of limited adhesivepower, bringing the surface of'said roller into contact with a travelling sheet of fibrous material provided with unset glue, and transferring said abrasive particles. to said sheet in discontinuous areas corresponding to the adhesive portions of the surface of said roller.

15.. A method of making an abrasive article which comprises the steps of depositing abrasive particles on a surface in a uniformly distributed and. uniform depth layer, moving said surface into proximity with an adhesive surface and then transferring said particles to said adhesive surface.

16. A method of making an abrasive article which comprises the steps of depositing abrasive particles on a surface in a uniformly distributed and uniform depth layer. moving said surface while said particles are so deposited into proximity with an adhesive surface and then transferring said particles to said adhesive surface.

17. A method of making an abrasive article which comprises the steps of depositing abrasive particles on a surface in a uniformly distributed and uniform depth layer, moving said surface into proximity with an adhesive surface and then transferring said particles in predesired location to: said adhesive surface.

18. A method of making an abrasive article which comprises the steps of depositing abrasive particles on a surface in a uniformly distributed and uniform depth layer, moving said surface into proximity with and underneath an adhesive surface and then transferring said particles .to said adhesive surface.

FREDERICK K. BEZZENBERGER. 

